1. Field of the Invention
The invention pertains to a strip-casting machine for producing a metal strip with two rotatably supported casting rolls set up next to each other to form a casting gap, where the casting rolls can be shifted away from the casting position to a servicing position and back again, and to a method for controlling the strip-casting machine.
2. Description of the Related Art
In strip-casting machines with two casting rolls, arranged essentially parallel to each other, side pieces are used to form the boundaries of the casting gap on the narrow sides. When strips, especially steel strips are cast, these side pieces are worn down by abrasive wear as a result of the friction with the casting rolls and also, in the lower part, by the friction with the solidified strip. When thus worn out, these side pieces must be replaced. So that they can be replaced, the side pieces are moved out of the casting position, in which they rest against the barrels, by means of the setting device in an essentially horizontal direction away from the barrels and into a setting position. Then side piece changing devices, e.g., robots, which are mounted on the casting platform on both sides of the machine, raise the side pieces up and out of the setting position. Japanese Patent Kokai JP-5[1993]-329,583 A, for example, describes robots of this type for replacing these side pieces.
In the known strip-casting machines, the casting rolls are stationary and are mounted rigidly underneath a ladle turret and a tundish vessel or the like. When these casting rolls must be serviced by regrinding or when they must be replaced, for example, a great deal of complicated disassembly and reassembly work is involved, because the casting rolls are difficult to access in themselves. Because of their weight, furthermore, they must be lifted away by a crane and set back into position again with an accuracy on the scale of millimeters. The connection and disconnection of the water lines or the electrical connecting lines is also associated with cumbersome work procedures because of the limited degree of accessibility present. It is even necessary to divide the structural frame on which the casting rolls are supported into two parts.
Another disadvantage of these known strip-casting machines is that, during the maintenance or servicing of the casting rolls or of the machine, no casting work can be done, which limits the casting output of the installation.
In a strip-casting machine of the general type in question according to WO-A 93/22,087, the casting rolls are supported on a cart, which can be moved along rails by a cylinder over a distance equal to approximately half the length of the cart. This design of the strip-casting machine, however, is suitable only for casting rolls of small diameter. The accessibility to the casting rolls in the servicing position a certain distance away from the casting position, furthermore, is still only slightly improved, because the rolls are still relatively close to the casting position.